Method and device for the retraction and hemostasis of tissue during crown and bridge procedures

ABSTRACT

A method and a device for effecting the cordless retraction of the gingival sulcus tissue prior to the taking of an impression of a tooth for making a crown or bridge which is attained by controlling any bleeding in the gingival sulcus area, and utilizing a dental dam preferably formed of a sponge or foam like material to contain an astringent fortified silicone impression material embedded about the prepared tooth, and using the patient&#39;s biting force to apply the necessary pressure onto the dam until the silicone impression material sets and adheres to the dam to enhance easy removal of the set impression material from the tooth. The dam is formed to accommodate either the posterior teeth or the anterior teeth.

FIELD OF THE INVENTION

[0001] This invention is directed to a method and device for effectinghemostasis retraction of tissue, and more specifically to a method anddevice for the retraction and hemostasis of tissue in preparing a toothprior to the taking of an impression for forming a crown or bridgedental prosthesis.

BACKGROUND OF THE INVENTION

[0002] The traditional method for controlling hemostasis and retractionof gingival tissue prior to the taking of an impression of a preparedtooth to form a crown or bridge is to mechanically pack a small lengthof cord saturated with an astringent about the base of the tooth toenlarge the gingival sulcus space about the base of a tooth. After aperiod of time, the cord is removed from the enlarged space definedabout the base of the tooth. Upon the removal of the cord, it frequentlyhappens that coagulum formed to stop the bleeding or seepage of fluid isremoved with the cord to result in the seepage of additional bleedinginto the space. As a result, an impression cannot be made of theprepared tooth until the additional bleeding can be controlled orstopped. Thus, the traditional procedure for enlarging the space betweenthe gum and the base of the tooth necessary for taking an accurateimpression is tedious, time consuming and painful or extremelyuncomfortable for the patient. Also, there exists the danger that thedentist may accidentally force the cord beyond the physiologic limit ofthe space to create a potential periodontal pocket which can cause thetooth to be eventually lost. The general practice of using the cordtechnique is relatively difficult and tedious for the dentist. In theevent that the space between the tooth and the gum that has to beretracted is very small, it becomes even more difficult for the dentistto place the cord without injuring the gum tissue and from forcing thecord beyond the physiologic limit, and renders the procedure morepainful for the patient. Further, the placing of the cord is not aprocedure which the dentist may delegate to a dental assistant or dentalhygienist. Also, the packing of a retraction cord is a most dislikedstep to perform during a crown or bridge restoration procedure.

[0003] Efforts have been made to obviate the noted disadvantages ofaffecting the retraction of the gingival tissue by the use of a cord.One such known effort is the use of a kaolin type material that is mixedwith an astringent salt which is simply placed about a prepared tooth toabsorb the moisture to cause the gum tissue to shrink. Such a product ismarketed by Sybron Dental Specialties under the brand name EXPASYL.

[0004] It has been noted that such kaolin type material is packaged in acartridge similar to a typical anesthetic cartridge commonly used in adental office that requires the cartridge to be used with a syringe. Theend of the cartridge is pierced with a needlelike cannula and the forceof the syringing pressure is required to extrude the clay like kaolinmaterial through the cannula. Because of the density of the kaolin typematerial, the cannula requires the opening to be very large so as toenable the kaolin type material to flow therethrough. The large guageopening of the cannula renders the bending of the cannula difficult andwhich bending is often required in order to place the material indifficult to reach places within a patient's mouth. Because the openingof the cannula is quite large, difficulty is encountered in placing thekaolin type material about the gingival sulcus in a manner similar tothe traditional method of packing cord to retract the gum tissue. Use ofsuch kaolin type material to retract the gum tissue tends to crumble,rendering it difficult to place in the space between the gum tissue andthe tooth to attain the desired retraction of the gum tissue. Anothernoted problem with such kaolin type material is the removal of thekaolin material after the period of time required to affect thehemostasis and the retraction. Generally, the kaolin material isrequired to be washed out using a water-air spray with extreme care toremove all the kaolin material without restarting any bleeding in thegingival sulcus.

[0005] Another known technique for effecting a non-cord retraction andhemostasis is disclosed in my prior U.S. Pat. No. 5,676,543. Thereindisclosed is a generally two part process utilizing two differentviscosities of a condensation silicone material to effect the cordlessretraction and hemostasis of the gingival sulcus.

[0006] This invention is directed to an improvement to the non-cordretraction and hemostasis procedure described in my prior U.S. Pat. No.5,676,543. This invention is directed to a more simplified non-cordretraction and hemostasis process and a device for accomplishing thesame.

SUMMARY OF THE INVENTION

[0007] An object of this invention is to provide a one part cordlessretraction method for enlarging the gingival sulcus space between thegum tissue and the prepared tooth prior to the taking of an impressionduring a crown or bridge procedure.

[0008] Another object is to provide a foam, rubber or sponge like damfor effecting the cordless retraction and hemostasis of the gingivalsulcus of a prepared tooth prior to the taking of an impression.

[0009] Another object is to provide for a hemostasis and cordlessretraction of the gingival sulcus using the patient's own bitingpressure to force the retraction material into the space between the gumtissue and the prepared tooth to enlarge the same.

[0010] Another object is to provide a cordless hemostasis and retractionmethod which is positive in operation and simple to perform.

[0011] Another object is to provide for a cordless hemostasis retractionmethod of the gingival sulcus area, which is painless, comfortable andeasy on the patient, and easy for the dentist to perform.

[0012] The foregoing objects and other features are attained by themethod of first preparing a tooth to be restored for taking animpression thereof in preparation of forming a crown or bridge. Afterthe tooth has been properly prepared and before a proper impression canbe made, the gum tissue about the base of the tooth must be retracted soas to enlarge the gingival sulcus. This is achieved in accordance withthis invention by the injection of a suitable liquid astringent aboutthe base of the tooth to control or stop any excessive bleeding orseepage of fluid. This can be attained by the application of a liquidhemostasis agent, e.g. aluminum chloride, ferric sulfate and the like tothe cut tissue by syringing or other suitable applicator. Where bleedingis slight or minimal, it may not be necessary to apply any astringent.After the controlled hemostasis, a foam or sponge like dam having agroove or trough is adjusted and fitted so as to cover at least onetooth mescal and distal beyond the prepared tooth. The foam or spongedam so formed is then filled with a silicone type impression materialwhich is fortified with a hemostatic agent. A predetermined amount ofthe fortified silicone impression material is also placed about theentire circumference of the prepared tooth at the gingival sulcusmargin, preferably by syringing. The application of the siliconeimpression material is then generously applied to cover the entireprepared tooth. The sponge or foam dam filled with the siliconeimpression material is then placed over the silicone covered tooth, atwhich time the patient is instructed to apply a biting pressure onto thesponge or foam dam and to maintain the biting pressure thereon for apredetermined time period sufficient for the silicone-impressionmaterial to set, e.g. 5 to 7 minutes. The sponge or foam dam is thenremoved together with the set or cured silicone material which remainsadhered to the sponge or foam dam. Upon removal of the dam, the toothmay be lightly washed and examined in preparation of the taking of theimpression. If additional retraction of the gum tissue is required, theprocedure may be repeated.

IN THE DRAWINGS

[0013]FIG. 1 is a side view of a prepared tooth and illustrating theplacement of a liquid hemostatic agent to control bleeding about thegingival sulcus area.

[0014]FIG. 2 illustrates the filling of the groove of a sponge or foamdam for use on posterior teeth with an amount of impression material.

[0015]FIG. 3 illustrates the intermediate step of placing the siliconeimpression material about the gingival sulcus area.

[0016]FIG. 4 illustrates the generous application of the siliconeimpression material covering the entire prepared tooth.

[0017]FIG. 5 illustrates the step of placing the filled sponge or foamdam onto the covering of the prepared tooth and the application of abiting pressure thereon.

[0018]FIG. 6 is a view similar to that of FIG. 5 to illustrate theretraction and enlargement of the space between the retracted gum tissueand the base of the prepared tooth with the dam and impression materialremoved.

[0019]FIG. 7 illustrates a perspective view of a slightly modifiedsponge or foam dam for use in the cordless retraction of the gum tissueabout anterior teeth.

DETAILED DESCRIPTION

[0020] Referring to the drawings, there is shown a tooth 20 which hasbeen prepared for receiving a crown or bridge. However, before theimpression can be taken for preparing the crown or bridge, it isimperative that the gingival sulcus tissue 21 be retracted in order forthe dentist to make an accurate impression of the prepared tooth 20. Inaccordance with this invention and to control any excessive gingivalbleeding, an application of a liquid hemostatic agent 22, e.g. aluminumchloride, ferric sulfate or other suitable astringent is applied to thecut tissue in the area of the gingival sulcus. The astringent can beapplied with Centrix's Benda micro applicator 23 as seen in FIG. 1, orby any other suitable applicator, e.g. Centrix, Inc.'s BENDA® brush,SoftStix™ disposable applicator, or syringe, and the like. Theastringent 22 is applied with moderate pressure and by rubbing theastringent solution against the cut tissue to infuse the astringentsolution into the cut capillaries. After the bleeding is under control,a dam 24 is adjusted and fitted to the prepared tooth 20 and to at leastone tooth mescal and distal beyond the prepared tooth or teeth 20.

[0021] In accordance with this invention, the dam 24 is formed of aporous foam or sponge type material which may be either natural orsynthetic. The dam 24, as shown in FIG. 4, is formed for use onposterior teeth.

[0022] As shown, the dam 24 may be formed as an elongated block of asponge, foam, or other type of porous material. It will be understoodthat the block of foam or sponge may be of any desired length from whichthe dentist may sever therefrom the desired length necessary to dam oneor more teeth being worked upon. Conversely, the dam 24 may be pre-cutto size, depending upon the number of teeth that may require gumretraction and to which the finished crown or bridge is to be applied.As seen in FIG. 4, the foam or sponge dam 24 is provided with alongitudinally U-shaped groove or trough 24A extending along the lengththereof. The respective opposed side walls 24B and 24C andinterconnected web or bottom 24D, as shown in FIG. 4, are sufficientlythick to contain and exert the necessary pressure to effect the gumtissue retraction as will be herein described.

[0023]FIG. 7 illustrates a modified block of sponge or foam materialfrom which a modified dam construction for use with anterior teeth isformed, as will be hereinafter described.

[0024] After the bleeding of the gum tissue to be retracted iscontrolled, the groove 24A of an appropriate size dam 24 is filled witha hereinbefore described fortified silicone type impression material 26,as shown in FIG. 2. The silicone material 26 may comprise a two-partcomposition which includes a base portion and a catalyst portion which,when mixed, will quickly set and become solid. The time of setting canbe varied within a predetermined time range by controlling the ratio ofcatalyst to base. Such silicones are available from variousmanufacturers, e.g. CONQUEST by Pentron, EXAFLEX by G. C., EXTRUDE byKerr Corporation or IMPRESS and EXPRESS by 3M Corporation. While thesilicone materials are preferred, other materials such as polyethers,polysulfides and any other dental moldable materials may be used. Thecondensation silicone materials are preferred. The silicone material 26is further fortified with between five percent (5%) to twenty percent(20%) by weight of a suitable astringent to aid in the gum tissueretraction and hemostasis. Any of the known astringents may be usedwhich are rendered compatible with the silicone. Some of the knownastringents or hemostasis agents are aluminum potassium sulfate,aluminum sulfate, or alum, ferric sulfate, aluminum ammonionium sulfate,ferric chloride, aluminum chloride, sodium chloride, zinc chloride andothers.

[0025] The same silicone material is also applied about the gingivalsulcus area as shown in FIG. 3, preferably by syringing. The entireprepared tooth 20 is then covered with the same silicone material asshown in FIG. 4. It will be understood that the step of applying thesilicone material to the dam 24 or about the tooth as shown in FIGS. 3and 4 can be reversed. With the tooth covered with the silicone material26, and with the groove 24A of the dam 24 filled with the same siliconematerial, the silicone-filled dam 24 is placed onto the silicone coveredtooth, as best seen in FIG. 5.

[0026] With the filled dam 24 disposed over the silicone covered toothor teeth, the patient is instructed to apply a biting force or pressureonto the dam 22 as shown in FIG. 5, and to maintain the biting pressureon the dam 24 until such time that the silicone material sets,approximately 5 to 7 minutes. Upon setting of the silicone material, thedam 24 and the set moldable material is removed to expose the preparedtooth as shown in FIG. 6. As the dam 24 is formed of a porous or foamsponge-like material, the silicone material, upon setting, willpenetrate the pores of the foam material, causing the set siliconematerial to mechanically adhere to the dam 24 whereby the set siliconematerial can be removed in unison upon the removal of the dam 24. Thetooth may then be lightly washed, dried and examined to determine if thegum tissue has been sufficiently retracted so as to enable an accurateimpression to be made.

[0027] The bite pressure imparted by the patient onto the dam 24 as seenin FIG. 5, causes the silicone impression material to be forced into thegingival sulcus space, which together with the interaction of theastringent material causes the gum tissue in the gingival sulcus area toretract to enlarge the space 27 between the tooth and surrounding gumtissue as noted in FIG. 6. In the event additional retraction of the gumtissue is required, the procedure hereinabove described may be repeated.

[0028] While the sponge or foam dams 24, as described herein, arepreferred, it will be understood that other means may be used in lieu ofthe foam or sponge dams, e.g. a cotton roll or hollowed cotton gauze orpad, or other suitable material capable of containing the silicone,astringent based, material when the biting pressure is applied andmaintained. The use of the biting pressure on the dam 24 causes thesilicone material containing the astringent material to be forced ontothe gingival sulcus space, causing the gum tissue to be retracted anamount sufficient to permit an accurate tooth impression to be made formaking a crown or bridge.

[0029] While the method described is in reference to retracting the gumtissue of a posterior tooth, the same method is applicable forretracting the gum tissue of an anterior tooth. However, for an anteriorgum retraction, the dam is preferably constructed with a V-shapedgroove, as in FIG. 7.

[0030] Referring to FIG. 7, an anterior dam 28 may be severed from anelongated block 29 of foam or sponge like material similar to thathereinbefore described, except the groove 30 is generally V-shaped asshown in FIG. 7. The opposed sides of the V-shaped groove 30 convergeinwardly of the foam or sponge block. In all other respects, theconstruction of dam 28 and the use thereof is similar to that describedwith respect to the construction and use of dam 24. It will beunderstood that the foam material, from which the described dams aremade, may be formed of open or closed cells, natural or synthetic foamor sponge.

[0031] The method described and the dam for effecting the same isrelatively simple, expedient and results in a positive retraction of thegum tissue so as to ensure that all margins can be captured in asubsequent impression procedure. The described invention further reducesthe trauma and discomfort often encountered by the patient in a gumretraction procedure. Also, the present invention provides enhancedresults with much greater ease on the part of the dentist. The procedureis rendered so simple that it can be delegated to a dental assistant.

[0032] While the preferred embodiments of the present invention havebeen illustrated and described, it will be obvious to those skilled inthe art that various modifications may be made without departing fromthe spirit and scope of this invention.

What is claimed is:
 1. A non-cord method of retracting gum tissue inpreparation for taking an impression comprising: (a) preparing a toothfor restoration; (b) controlling any bleeding occurring with respect toany cut tissue in the gingival sulcus area; (c) placing an amount of animpression material into the groove of a dental dam; (d) covering theprepared tooth with a layer of said impression material; (e) placing thetrough of the dental dam filled with the impression material onto theprepared tooth covered with said silicone material; (f) requiring thepatient to apply a biting pressure onto dental dam; (g) and maintainingthe biting pressure on the dental dam until the impression material hasset.
 2. A non-cord method of retracting gum tissue as defined in claim 1wherein steps (c) and (d) may be reversed.
 3. A non-cord method ofretracting gum tissue as defined in claim 1 and including the step ofusing a dental dam formed of a porous material.
 4. A non-cord method ofretracting gum tissue as defined in claim 1 wherein the dental dam isformed of a porous foam material.
 5. A non-cord method of retracting gumtissue as defined in claim 4 wherein: said dental dam is formed as anelongated block of said foam material having a groove extendinglongitudinally of said block, and said block being of sufficientthickness to retain the impression material confined within said groovewhen a biting pressure is applied thereto.
 6. A non-cord method ofretracting gum tissue as defined in claim 1 wherein said impressionmaterial used comprises a two-part composition which includes a baseportion and a catalyst portion which, when mixed, will quickly set.
 7. Anon-cord method of retracting gum tissue as defined in claim 6 whereinsaid composition used is fortified with an astringent selected from thegroup consisting of aluminum potassium sulfate, potassium aluminumsulfate, aluminum sulfate, alum, ferric sulfate, aluminum ammonioniumsulfate, ferric chloride, aluminum chloride, sodium chloride and zincchloride.
 8. A non-cord method of retracting gum tissue for taking atooth impression comprising: (a) controlling any bleeding occurring withrespect to any cut tissue in the gingival sulcus area; (b) covering theprepared tooth with a generous amount of impression material; (c)placing the groove of a dental dam onto the prepared tooth covered withthe impression material; (d) requiring the patient to apply a bitingpressure onto the dental dam; (e) and maintaining the biting pressure onthe dental dam until the impression material has set.
 9. A non-cordmethod of retracting gum tissue as defined in claim 8 wherein saiddental dam is formed of a cellular foam material.
 10. A non-cord methodof retracting gum tissue in preparation for taking a tooth impressioncomprising: (a) placing an amount of an impression material into thegroove of a dental dam; (b) covering the prepared tooth with a layer ofsaid impression material; (c) placing the trough of the dental damfilled with the impression material onto the prepared tooth covered withsaid silicone material; (d) requiring the patient to apply a bitingpressure onto dental dam; (e) and maintaining the biting pressure on thedental dam until the impression material has set.
 11. A device foreffecting the cordless retraction of gum tissue comprising: a block of acellular material of a size to receive a prepared tooth; said blockhaving a groove extending co-extensively thereof to form a dental dam;said groove being adapted to receive the prepared tooth; and said groovebeing adapted to be filled with an impression material whereby saidfilled groove is fitted to the prepared tooth covered with an impressionmaterial.
 12. A device as defined in claim 11 wherein said groove isU-shaped, and said dental dam having opposed side walls defining saidgroove, said side walls being of sufficient thickness to contain theimpression material when a biting force is applied thereto.
 13. A deviceas defined in claim 11 wherein said groove is V-shaped for use with theanterior teeth.
 14. A device as defined in claim 11 wherein saidcellular material comprises a synthetic foam material.
 15. A device asdefined in claim 11 wherein said cellular material comprises a sponge.